This White Paper presents the scientific rationale and instrument concept for HRMOS (High-Resolution Multi-Object Spectrograph), a next-generation instrument proposed for the ESO Very Large Telescope within the VLT 2030 roadmap. Current and planned facilities offer either multi-object spectroscopy or ultra-high spectral resolution, but not both. HRMOS fills this gap by combining very high spectral resolution, multi-object capability, and radial-velocity stability, enabling transformative studies in Galactic and extragalactic astrophysics. The baseline design provides a resolving power of R = 80000, radial-velocity precision of 10 m s-1 (goal: 5 m s-1), simultaneous observations of 50-60 targets, and broad optical coverage down to 385 nm. These capabilities enable precise measurements of elemental abundances, isotopic ratios, line profiles, and radial velocities for large stellar samples, including crowded fields, star clusters, the Galactic bulge, and nearby dwarf galaxies. HRMOS will address key questions on the age of the oldest stellar populations through nucleocosmochronology, the formation and survival of planetary systems, the assembly history of the Milky Way and satellites, the origin of the heaviest elements, stellar evolution, and the chemical and dynamical properties of the interstellar and circumgalactic medium. It will bridge large spectroscopic surveys and the next generation of extremely large telescopes, with strong synergies with 4MOST, Gaia, TESS, PLATO, the proposed Haydn mission, and future ELT instruments. Building on VLT/FLAMES heritage, HRMOS represents a strategic investment for European astronomy in the 2030s.

The Prime Focus Spectrograph (PFS) is a new optical/near-infrared multi-fiber spectrograph designed for the prime focus of the 8.2m Subaru telescope. PFS will cover 1.3 degrees diameter field with 2394 fibers to complement the imaging capability of Hyper SuprimeCam (HSC). The prime focus unit of PFS called Prime Focus Instrument (PFI) provides the interface with the top structure of Subaru telescope and also accommodates the optical bench in which Cobra fiber positioners and fiducial fibers are located. In addition, the acquisition and guiding cameras (AGCs), the cable wrapper, the fiducial fiber illuminator, and viewer, the field element, and the telemetry system are located inside the PFI. The mechanical structure of the PFI was designed with special care such that its deflections sufficiently match those of the HSC’s Wide Field Corrector (WFC) so the fibers will stay on targets over the course of the observations within the required accuracy. The assembly, integration and verification of PFI was completed in 2021. The performance of PFI meets the requirements and it was delivered to Subaru telescope in June 2021. Consequently, various tests and engineering runs were carried out to calibrate the PFI and verify the performance of the PFI with the telescope.

With this work we summarise the design evolution and challenges of the Fiber-Link module for ANDES (ArmazoNes high Dispersion Echelle Spectrograph), the high resolution spectrograph for ESO ELT. The instrument just passed the System Architecture Review of Phase-B1. The Fiber-Link subsystem carries and redistributes the light from the telescope to the spectrometers via several selectable optical paths. The general updated layout for the Fiber-Link module is presented giving element characteristics and obtained performances. First results from laboratory test and prototype activities are also shown. Moreover, we include the reasoning for selected solutions and explaining how requirements are met. Finally, we summarise the compliance against the science top-level requirements and the issues to address moving forward.

For the fifth Sloan Digital Sky Survey, SDSS-V, we moved one of the two SDSS BOSS spectrographs from Apache Point Observatory in New Mexico to Las Campanas Observatory in Chile, giving us dual-hemisphere coverage. Modifications for connecting to a new robotic fiber positioner included replacing the old fiber slit with a monolithic fiber slit made of a precision-machined glass mount presenting 528 fibers. To construct this slit, V-grooves were cut into a borosilicate glass substrate and fibers were glued into them under a cover plate. This glass slit was then attached to an Alloy 39 (steel) flexure, which in turn was affixed to a thin slit plate made of cast aluminum for insertion into the spectrograph. Because our existing spare parts inventory would not support two distant locations, and because many parts were no longer manufactured, some spectrograph subsystems were replaced with new components or designs.

A major endeavor of this decade is the direct characterization of young giant exoplanets at high spectral resolution to determine the composition of their atmosphere and infer their formation processes and evolution. Such a goal represents a major challenge owing to their small angular separation and luminosity contrast with respect to their parent stars. Instead of designing and implementing completely new facilities, it has been proposed to leverage the capabilities of existing instruments that offer either high-contrast imaging or high-dispersion spectroscopy by coupling them using optical fibers. In this work, we present the implementation and first on-sky results of the High-Resolution Imaging and Spectroscopy of Exoplanets (HiRISE) instrument at the Very Large Telescope (VLT), which combines the exoplanet imager SPHERE with the recently upgraded high-resolution spectrograph using single-mode fibers. The goal of HiRISE is to enable the characterization of known companions in the $H$ band at a spectral resolution on the order of $R = = 100\,000$ in a few hours of observing time. We present the main design choices and the technical implementation of the system, which is constituted of three major parts: the fiber injection module inside of SPHERE, the fiber bundle around the telescope, and the fiber extraction module at the entrance of We also detail the specific calibrations required for HiRISE and the operations of the instrument for science observations. Finally, we detail the performance of the system in terms of astrometry, temporal stability, optical aberrations, and transmission, for which we report a peak value of sim 3.9 based on sky measurements in median observing conditions. Finally, we report on the first astrophysical detection of HiRISE to illustrate its potential.

We present the results of optical performance verification for the Prime Focus Spectrograph (PFS) fiber optics module, so-called "CableBs", at Subaru Telescope. PFS is the next generation ultra-wide field multi object spectrograph. It employs 2386 fibers of which the fiber tips are placed precisely on the primary focal plane over a field of view of 1.3 degrees in diameter. CableB transfers light from the fiber positioning module, or Prime Focus Instrument, to the spectrographs. PFS utilizes four CableBs and each of them carries just over 600 science grade fibers. We completed installation of all CableBs at the telescope in June 2023 after two-years of intermittent work. The optical performance of each CableB was subsequently assessed, focusing on four areas; continuity, uniformity, throughput, and focal ratio degradation (FRD). For examining continuity, we illuminated one termination of CableB with flat LED panel and observed the transmitted light. We found only one fiber newly broken during shipment from the integration site. We also checked uniformity of the relative intensity of light propagating in each fiber. The whole variations around the average intensities fit in 20% range among fibers in each CableB, which was consistent with the measurement before shipping. Throughput of sampled fibers were measured in a wavelength range from 400 to 1400 nm with commercial spectrometers. The measurement at the telescope and the integration site each showed a throughput of approximately 70%, so both sets of measurements are consistent. Finally, we measured FRD employing the collimated beam method to ensure that CableBs were free from any significant physical stress after the installation. Our FRD measurements were comparable before and after the installation. In addition, a long-term monitoring of over a few months showed FRD remained sufficiently stable for science operations. According to these results, we conclude that the installation of CableBs at Subaru Telescope was successful.

The first generation of ELT instruments includes an optical-infrared High Resolution Spectrograph: ANDES (ArmazoNes high Dispersion Echelle Spectrograph). This paper describes the design of the Integral Field Unit (IFU): the focal plane of the ELT is reimaged at different scales (down to the diffraction limit) and fed into a bundle of fibers that covers a small hexagonal field of view that terminate in a linear structure aligned along the spectrometer slit.

The first generation of ELT instruments includes an optical-infrared High Resolution Spectrograph, formerly indicated as ELT-HIRES and recently christened ANDES (ArmazoNes high Dispersion Echelle Spectrograph). This paper describes the design of the fiber link that carries the light from the telescope to the spectrometers via several selectable optical paths that in turn define the two baseline observing modes of the instrument, namely: – Seeing limited observing mode, where the light from the ELT is collected by two large fibers (~0.8" sky projected diameter) and is uniformly redistributed into smaller fibers that terminate in a linear structure aligned along the spectrometer slit. – Integral field (IFU) observing mode, where the focal plane of the ELT is reimaged at different scales (down to the diffraction limit) and fed into a bundle of fibers that covers a small hexagonal field of view and terminate in a linear structure aligned along the spectrometer slit.

The Prime Focus Spectrograph (PFS) is a new optical/near-infrared multi-fiber spectrograph designed for the prime focus of the 8.2m Subaru telescope. PFS will cover 1.3 degrees diameter field with 2394 fibers to complement the imaging capability of Hyper SuprimeCam (HSC). The prime focus unit of PFS called Prime Focus Instrument (PFI) provides the interface with the top structure of Subaru telescope and also accommodates the optical bench in which Cobra fiber positioners and fiducial fibers are located. In addition, the acquisition and guiding cameras (AGCs), the cable wrapper, the fiducial fiber illuminator, and viewer, the field element, and the telemetry system are located inside the PFI. The mechanical structure of the PFI was designed with special care such that its deflections sufficiently match those of the HSC's Wide Field Corrector (WFC) so the fibers will stay on targets over the course of the observations within the required accuracy. The assembly, integration and verification of PFI was completed in 2021. The performance of PFI meets the requirements and it was delivered to Subaru telescope in June 2021. Consequently, various tests and engineering runs were carried out to calibrate the PFI and verify the performance of the PFI with the telescope.

PFS (Prime Focus Spectrograph), a next generation facility instrument on the Subaru telescope, is now being tested on the telescope. The instrument is equipped with very wide (1.3 degrees in diameter) field of view on the Subaru’s prime focus, high multiplexity by 2394 reconfigurable fibers, and wide waveband spectrograph that covers from 380nm to 1260nm simultaneously in one exposure. Currently engineering observations are ongoing with Prime Focus Instrument (PFI), Metrology Camera System (MCS), the first spectrpgraph module (SM1) with visible cameras and the first fiber cable providing optical link between PFI and SM1. Among the rest of the hardware, the second fiber cable has been already installed on the telescope and in the dome building since April 2022, and the two others were also delivered in June 2022. The integration and test of next SMs including near-infrared cameras are ongoing for timely deliveries. The progress in the software development is also worth noting. The instrument control software delivered with the subsystems is being well integrated with its system-level layer, the telescope system, observation planning software and associated databases. The data reduction pipelines are also rapidly progressing especially since sky spectra started being taken in early 2021 using Subaru Nigh Sky Spectrograph (SuNSS), and more recently using PFI during the engineering observations. In parallel to these instrumentation activities, the PFS science team in the collaboration is timely formulating a plan of large-sky survey observation to be proposed and conducted as a Subaru Strategic Program (SSP) from 2024. In this article, we report these recent progresses, ongoing developments and future perspectives of the PFS instrumentation.

The combination on large ground-based telescopes of extreme adaptive optics (ExAO), coronagraphy and high-dispersion spectroscopy is starting to emerge as a powerful technique for the direct characterisation of giant exoplanets. High spectral resolution not only brings a major gain in terms of accessible spectral features, but it also enables to better disentangle between the stellar and planetary signals thanks to the much higher spectral content. On-going projects such as KPIC for Keck, REACH for Subaru and HiRISE for the VLT base their observing strategy on the use of a few science fibres, one of which is dedicated to sampling the PSF of the planet, while the others sample the stellar residuals in the speckle field. The main challenge in this approach is to blindly centre the science fibre on the planet’s PSF, with typically a tolerance of less than one resolution element (0.1 λ/D). Several possible centring strategies can be adopted, either based on calibration fibres retro-injecting signal to mark the position of the science fibres or based on the use of focal-plane features introduced by the ExAO system. In this proceeding, we describe different possible approaches and we compare their centring accuracy using the MITHiC high-contrast imaging testbed. For this work, MITHiC has been upgraded to reproduce a setup close to the one that will be adopted in HiRISE, the coupling system that will soon be implemented between VLT/SPHERE and VLT/CRIRES+. Our results demonstrate that reaching a specification accuracy of 0.1 λ/D is extremely challenging regardless of the chosen centring strategy. It requires a high level of accuracy at every step of the centring procedure, which can be reached with very stable instruments. We studied the contributors to the centring error in the case of MITHiC and we quantified some of the most important terms.

New generation exoplanet imagers on large ground-based telescopes are highly optimised for the detection of young giant exoplanets in the near-infrared, but they are intrinsically limited for their characterisation by the low spectral resolution of their integral field spectrographs (R < 100). High-dispersion spectroscopy at R ≫ 104 would be a powerful tool for the characterisation of these planets, but there is currently no high-resolution spectrograph with extreme adaptive optics and coronagraphy that would enable such characterisation. With project HiRISE we propose to use fiber coupling to combine the capabilities of two flagship instruments at the Very Large Telescope in Chile: the exoplanet imager SPHERE and the high-resolution spectrograph CRIRES+. The coupling will be implemented at the telescope in early 2023. We provide a general overview of the implementation of HiRISE, of its assembly, integration and testing (AIT) phase in Europe, and a brief assessment of its expected performance based on the final hardware.

On large ground-based telescopes, the combination of extreme adaptive optics (ExAO) and coronagraphy with high-dispersion spectroscopy (HDS), sometimes referred to as high-dispersion coronagraphy (HDC), is starting to emerge as a powerful technique for the direct characterisation of giant exoplanets. The high spectral resolution not only brings a major gain in terms of accessible spectral features but also enables a better separation of the stellar and planetary signals. Ongoing projects such as Keck/KPIC, Subaru/REACH, and VLT/HiRISE base their observing strategy on the use of a few science fibres, one of which is dedicated to sampling the planet's signal, while the others sample the residual starlight in the speckle field. The main challenge in this approach is to blindly centre the planet's point spread function (PSF) accurately on the science fibre, with an accuracy of less than 0.1 λ/D to maximise the coupling efficiency. In the context of the HiRISE project, three possible centring strategies are foreseen, either based on retro-injecting calibration fibres to localise the position of the science fibre or based on a dedicated centring fibre. We implemented these three approaches, and we compared their centring accuracy using an upgraded setup of the MITHiC high-contrast imaging testbed, which is similar to the setup that will be adopted in HiRISE. Our results demonstrate that reaching a specification accuracy of 0.1 λ/D is extremely challenging regardless of the chosen centring strategy. It requires a high level of accuracy at every step of the centring procedure, which can be reached with very stable instruments. We studied the contributors to the centring error in the case of MITHiC and we propose a quantification for some of the most impacting terms.

In this paper, we present the beginning of the last phase of the integration process of the FOCCoS subsystem, "Fiber Optical Cable and Connector System", to be installed on the Subaru telescope as part of the PFS (Prime Focus Spectrograph) project [01]. FOCCoS consists of the 3 cables (A, B and C) to integrate and operate the instruments easily [02]. At the present stage, we are about to complete the integration of the 3 cables by building Cable B that intermediates the telescope’s light gathering and light output devices for the spectrographs. Cable B, which is ~55m long, is subdivided into 4 units. Each unit has 600 optical fibers inserted into segmented tubes that are helically stranded around the tensile core element and inserted into a flexible metal conduit, which was made by industrial process. The construction of Cable B unit involves a coherent fiber distribution for a required mapping between the light collecting ends and the output ends positioned on the slits. Multi-fiber connector bench, strain relief boxes, and connection monitoring fiber devices are being built as part of subsystem integration process. Specific FRD measurement procedures for Cable B have been fully developed and implemented. The measurements are so far indicating similarly good results to those obtained in the evaluation of fibers from Cables A and C. For Cable B, FRD of some fibers has been traced to monitor the impact of the integration process.

PFS (Prime Focus Spectrograph), a next generation facility instrument on the Subaru telescope, is a very wide- field, massively multiplexed, and optical and near-infrared spectrograph. Exploiting the Subaru prime focus, 2394 reconfigurable fibers will be distributed in the 1.3 degree-diameter field of view. The spectrograph system has been designed with 3 arms of blue, red, and near-infrared cameras to simultaneously deliver spectra from 380nm to 1260nm in one exposure. The instrumentation has been conducted by the international collaboration managed by the project office hosted by Kavli IPMU. The team is actively integrating and testing the hardware and software of the subsystems some of which such as Metrology Camera System, the first Spectrograph Module, and the first on-telescope fiber cable have been delivered to the Subaru telescope observatory at the summit of Maunakea since 2018. The development is progressing in order to start on-sky engineering observation in 2021, and science operation in 2023. In parallel, the collaboration is trying to timely develop a plan of large-sky survey observation to be proposed and conducted in the framework of Subaru Strategic Program (SSP). This article gives an overview of the recent progress, current status and future perspectives of the instrumentation and scientific operation.

HIRES is the high-resolution spectrograph of the European Extremely Large Telescope at optical and near-infrared wavelengths. It consists of three fibre-fed spectrographs providing a wavelength coverage of 0.4-1.8 µm (goal 0.35-2.4 µm) at a spectral resolution of 100,000. The fibre-feeding allows HIRES to have several, interchangeable observing modes including a SCAO module and a small diffraction-limited IFU in the NIR. Therefore, it will be able to operate both in seeing- and diffraction-limited modes. Its modularity will ensure that HIRES can be placed entirely on the Nasmyth platform, if enough mass and volume is available, or part on the Nasmyth and part in the Coud`e room. ELT-HIRES has a wide range of science cases spanning nearly all areas of research in astrophysics and even fundamental physics. Among the top science cases there are the detection of biosignatures from exoplanet atmospheres, finding the fingerprints of the first generation of stars (PopIII), tests on the stability of Nature's fundamental couplings, and the direct detection of the cosmic acceleration. The HIRES consortium is composed of more than 30 institutes from 14 countries, forming a team of more than 200 scientists and engineers.

HIRES will be the high-resolution spectrograph of the European Extremely Large Telescope at optical and near-infrared wavelengths. It consists of three fibre-fed spectrographs providing a wavelength coverage of 0.4-1.8 mic (goal 0.35-1.8 mic) at a spectral resolution of ~100,000. The fibre-feeding allows HIRES to have several, interchangeable observing modes including a SCAO module and a small diffraction-limited IFU in the NIR. Therefore, it will be able to operate both in seeing and diffraction-limited modes. ELT-HIRES has a wide range of science cases spanning nearly all areas of research in astrophysics and even fundamental physics. Some of the top science cases will be the detection of bio signatures from exoplanet atmospheres, finding the fingerprints of the first generation of stars (PopIII), tests on the stability of Nature's fundamental couplings, and the direct detection of the cosmic acceleration. The HIRES consortium is composed of more than 30 institutes from 14 countries, forming a team of more than 200 scientists and engineers.

ELT-HIRES is the high resolution and ultra-stable Echelle spectrograph for the ELT. It has been conceived as a modular instrument provided with two independent spectrometers (the baseline design) and a possible extension to four, each of them optimized to cover a fixed spectral range. The role of the fibers is essential to provide the required ultrastability. Placed at the Nasmyth focus of the ELT, the HIRES fiber link transfers the light from the focal plane to the spectrographs. Each observing modes will be use a unique and independent group of fibers (bundle). The HIRES modular design makes it possible to have new observing modes just with the addition, removal or change of the specific bundles. From a functional point of view the HIRES fiber link subsystem performs some other important tasks, such as dicing the field of view, improving the system stability and providing a uniformly illuminated slit for spectrographs. It is a key subsystem for the instrument and represents a significant technological challenge. The technical requirements, conceptual design and technologies to be used are discussed in this paper. The current status of the subsystem, and future plans are also addressed.